here is abc's martha raddatz. >> reporter: the u.s. navy reconnaissance plane circled yemen's capital, scouring the streets and alley ways below searching for terrorist operatives behind a plan, u.s. intelligence believes, involves a strike on the u.s. embassy or western targets with explosive-laden trucks. iona craig, a freelance journalist in the city described the eyes in the sky. >> it was buzzing for at least five hours. then a break for about an hour, maybe two, and then the was back again. >> reporter: taking no chances the u.s. air force, air lifted almost all of the u.s. personnel out to safety. leaving only the most essential personnel behind. we know this is the man behind the plot, a hardened leader, determined to strike beyond the borders of yemen to the american moem land. homeland. he was behind the underwear bombing plot to bring down a u.s. aircraft. he just might get help from a large number of maximum security prisoners many of them al qaeda who have been busted out of jail in recent weeks with the help of heavily ar